How can public transit get people out of their cars? An analysis of transit mode choice for commute trips in Los Angeles

- I explore strategies to reduce auto dependence & promote discretionary transit use.
- I analyze contexts in which car-owners in Los Angeles choose transit for commuting.
- Findings reveal the importance of fast, frequent, reliable transit service with fewer transfers.
- Increasing traffic congestion may not automatically get people out of their cars.

U.S. public transit agencies struggle to attract and retain riders. Unprecedented public investments have been made over the past several decades for expanding and improving transit service across cities. Unfortunately, however, there is no evidence of increase in ridership once growth in population and aggregate travel demand are accounted for. Consequently, the quest for boosting patronage continues. The challenge, experts argue, is to attract people out of cars.In this paper, I use a recent state-wide travel survey from California and take advantage of a new comprehensive historical archive of regional real-time multi-modal transportation system data to explore contexts in which persons belonging to car-owning households within Los Angeles County use transit for their commute.I find that few car owners use transit, and that lack of access to the household vehicle(s) explain choice of transit to a large extent. While discretionary transit use (or transit use by choice) is rare, I find evidence that fast (relative to car), frequent and reliable transit service along with fewer transfer requirements strongly correlate with car-owners' transit mode choice. Home and workplace neighborhood density, proximity to transit stop, and availability of rail are other critical facilitators. Even if observed effects are due, in part, to self-selection, there are important lessons for transit planners. For example, results suggest that all else equal: reduction in transit-to-auto travel time ratio by unity can increase odds of transit mode choice by about 25%; reduction in headway by 10 min can increase the odds by about 30%, and; lowering the standard deviation of schedule deviation from over to under three minutes can result in 2.6 times increase in the odds.This paper identifies effective strategies for increasing transit's competitiveness relative to auto, and hence attracting people out of their cars. While rail network expansion programs and transit-oriented development efforts must continue across U.S. cities, it is important that planners also advocate for investments in key dimensions of bus service quality that patrons value, such as speed, frequency and reliability. Efficient network designs that reduce transfer requirements, introduction of bus rapid transit services, and improvements in real-time operations, scheduling and long-range planning by using ITS (intelligent transportation systems) infrastructures across modes are critical. This study shows that careful planning can promote discretionary transit use by attracting existing latent demand and by creating new demand in an era of increasing government interest in transit and growing traffic congestion. Broader positive effects on the travelling public and the environment are much greater than what this study can predict.